Vespers Rising (The 39 Clues #11)

A new enemy. An even deadlier challenge. The NEW YORK TIMES best-selling series returns. The Cahills thought they were the most powerful family the world had ever known. They thought they were the only ones who knew about Gideon Cahill and his Clues. The Cahills were wrong.

Long Synopsis:

A new enemy. An even deadlier challenge. The NEW YORK TIMES best-selling series returns. The Cahills thought they were the most powerful family the world had ever known. They thought they were the only ones who knew about Gideon Cahill and his Clues. The Cahills were wrong. Powerful enemies -- the Vespers -- have been waiting in the shadows. Now it's their time to rise and the world will never be the same.